Sterile containment welding devices are known for connecting and disconnecting plastic tubes. Examples of such devices are found in U.S. Pat. Nos. 5,256,229, 5,279,685 and 5,397,425. In general, such devices include a pair of tube holders which would be in alignment with each other. Each of the tube holders has a base with the tube receiving channel into which a plastic tube would be placed. Each tube holder also includes a clamping jaw having a ram and anvil located above the channel. Thus, for example, when a tube is placed in the channel the clamping jaw is moved into locking engagement with the base and the anvil presses against the tube. In one practice of such devices each tube is placed in its channel in a bent condition by being bent upon itself with the bend of the tube extending outwardly from the outer edge of the channel. Thus, in a connect procedure the pair of bent ends would be disposed toward each other with each bent section in alignment with a corresponding bent section of the opposite tube holder. The connect procedure is achieved by passing a heated wafer between the two bent tube ends which causes the tube ends to melt so that a tube section from each tube can be pressed into contact with a corresponding tube section from the other tube and thereby join the two sets of tube sections together.
It is known to include in such devices a thermocouple which monitors the temperature of the heater device so that there is assurance that the wafer will be heated to the desired predetermined temperature. In operation when the device is actuated the heater operates continuously to raise its temperature until the desired temperature is reached. The thermocouple, which is separate from the heater, monitors the temperature rise to sense reaching the desired temperature.